Digital Subscriber Line (DSL) is a technology for bringing high-bandwidth digital information to homes and businesses over telephone lines. A DSL line can simultaneously carry both data and voice signals. The data portion of the line may be continuously available to the user, making DSL an “always-on” connection. Special digital hardware attached to both ends of the line allows data transmission over the wires at relatively high bandwidths.
DSL is offered to subscribers by DSL providers. DSL providers connect DSL modems, through a digital subscriber line, to a central office. Typically, the distance between the user and the central office must be less than a certain distance, such as about four miles, for the DSL connection to operate properly. At the central office, signals from the DSL subscriber may be packetized and transmitted to a larger network, such as an asynchronous transfer mode (ATM) network that connects to an Internet Service Provider (ISP).
When installing or repairing a DSL connection a technician typically visits the subscriber's premise to test the service. To test the DSL service, the technician may use one or more devices carried by the technician and that the technician plugs into the line. The device(s) may provide information relating to the quality of the connection, such as maximum bit rate, error rate, and noise level of the line. Based on this information, the technician may determine whether the subscriber is experiencing an acceptable level of service.